Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

qherring · 2023-06-27 08:27:49

I was trying to add an allow-discards parameter to the kernel command and I completely broke Grub. I cannot boot up nor can I boot into any of my snapper snapshots. I have a fully encrypted btrfs disk. Here is what I did to cause this:

I added a line in /etc/default/grub:

cryptsetup refresh —allow-discards cryptlvm

Then in a terminal I did sudo grub-mkconfig -o /boot/grub/grub.cfg

I then rebooted and now I am stuck. Each time I try to boot up it says:

ERROR: device 'UUID-df9abdc3-3c8a-4908-b91d-250cdddd73fe' not found. Skipping fsck. mount:/new_root:can't find UUID=df9abdc3-3c8a-4908-b91d-250cdddd73fe. ERROR: Failed to mount 'UUID = df9abdc3-3c8a-4908-b91d-250cdddd73fe' on real root You are now being dropped into an emergency shell. sh: can't access tty: job control turned off [rootfs]#

Please help me rectify this. I am devastated. What a bad day…

Last edited by qherring (2023-06-27 19:20:57)

jl2 · 2023-06-27 08:30:56

This isn't grub. you're already booting the kernel.
Did you change anything with your disk layout (remove partitions?)?
I get identical errors when I add/remove partitions and forget to edit fstab (don't, I don't know how it works with encryptions).

Last edited by jl2 (2023-06-27 08:34:07)

qherring · 2023-06-27 08:36:36

No the only thing I changed is the what is written above. I booted fine 1 minute before I ran sudo grub-mkconfig -o /boot/grub/grub.cfg

jl2 · 2023-06-27 08:43:21

well then https://archlinux.org/news/grub-bootloa … ibilities/

qherring · 2023-06-27 08:44:54

I have another arch install up and running on a different SSD on the same computer. Is there a way I can mount the drive and amend from there?

seth · 2023-06-27 08:45:10

Boot a live system, post the output of "lsblk -f"
Mount the root and post /mnt/etc/fstab, see whether there's anything in /mnt/boot
Mount your /boot partition to /mnt/boot, post /mnt/boot/grub/grub.cfg

Edit: https://wiki.archlinux.org/title/Chroot

Last edited by seth (2023-06-27 08:51:06)

nl6720 · 2023-06-27 08:46:30

qherring wrote:

UUID-df9abdc3-3c8a-4908-b91d-250cdddd73fe

qherring wrote:

UUID=df9abdc3-3c8a-4988-b91d-250cdddd73fe

qherring wrote:

UUID = df9abdc3-3c8a-4908-b91d-250cdddd73fe

These shouldn't differ.
I'm guessing you made some typo when editing /etc/default/grub.

Also I don't think you need to add "allow-discards" to the kernel command line if the option is set in the LUKS2 header.

jl2 · 2023-06-27 08:47:03

you can just install it from there without chrooting.
grub-install --target=x86_64-efi --efi-directory=esp --bootloader-id=GRUB
use the esp of your other install.
EDIT: you do have to arch-chroot for grub-mkconfig
mount root /mnt
mount esp /mnt/boot
arch-chroot /mnt
EDIT2: nvm - i think that isn't the problem

Last edited by jl2 (2023-06-27 08:51:38)

qherring · 2023-06-27 08:56:50

nl6720 wrote:

qherring wrote:
UUID-df9abdc3-3c8a-4908-b91d-250cdddd73fe
qherring wrote:
UUID=df9abdc3-3c8a-4988-b91d-250cdddd73fe
qherring wrote:
UUID = df9abdc3-3c8a-4908-b91d-250cdddd73fe
These shouldn't differ.
I'm guessing you made some typo when editing /etc/default/grub.

I made a typo when bringing from the terminal to this forum. they are all the same

Last edited by qherring (2023-06-27 08:57:02)

qherring · 2023-06-27 08:58:28

seth wrote:

Boot a live system, post the output of "lsblk -f"
Mount the root and post /mnt/etc/fstab, see whether there's anything in /mnt/boot
Mount your /boot partition to /mnt/boot, post /mnt/boot/grub/grub.cfg
Edit: https://wiki.archlinux.org/title/Chroot

This is the lsblk -f for the drive Im trying to fix:

nvme1n1
├─nvme1n1p1 vfat FAT32 8F49-4391
└─nvme1n1p2 crypto_LUKS 2 b7b560e0-b889-4f66-a24e-90280eb81b2a
└─luks-b7b560e0-b889-4f66-a24e-90280eb81b2a btrfs df9abdc3-3c8a-4908-b91d-250cdddd73fe 3.6T 0% /run/media/qherring/df9abdc3-3c8a-4908-b91d-250cdddd73fe

Last edited by qherring (2023-06-27 09:11:50)

seth · 2023-06-27 09:00:47

Don't transcribe that (and the other things) manually!
See the 1st link below.

qherring · 2023-06-27 09:03:54

seth wrote:

Mount the root and post /mnt/etc/fstab, see whether there's anything in /mnt/boot

when I try:

sudo mount /dev/mapper/cryptlvm -o subvolid=5 /mnt

I get:

mount: /mnt: special device /dev/mapper/cryptlvm does not exist.
dmesg(1) may have more information after failed mount system call.

seth · 2023-06-27 09:10:04

You'll first have to "cryptsetup open" it?
https://wiki.archlinux.org/title/Dm-cry … encryption

qherring · 2023-06-27 09:15:10

Here is /etc/fstab

# Static information about the filesystems.
# See fstab(5) for details.

# <file system> <dir> <type> <options> <dump> <pass>
# /dev/mapper/ainstnvme1n1p2
UUID=df9abdc3-3c8a-4908-b91d-250cdddd73fe / btrfs rw,noatime,compress=zstd,subvol=/@ 0 0

# /dev/mapper/ainstnvme1n1p2
UUID=df9abdc3-3c8a-4908-b91d-250cdddd73fe /.snapshots btrfs rw,noatime,compress=zstd,subvol=/@snapshots 0 0

# /dev/nvme1n1p1
UUID=8F49-4391 /boot vfat rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro 0 2

# /dev/mapper/ainstnvme1n1p2
UUID=df9abdc3-3c8a-4908-b91d-250cdddd73fe /home btrfs rw,noatime,compress=zstd,subvol=/@home 0 0

# /dev/mapper/ainstnvme1n1p2
UUID=df9abdc3-3c8a-4908-b91d-250cdddd73fe /var/log btrfs rw,noatime,compress=zstd,subvol=/@var_log 0 0

qherring · 2023-06-27 09:17:56

I was able to mount in on the GUI

/boot is empty on that disk

seth · 2023-06-27 09:32:23

We're still missing the grub.cfg (being the most relevant part here) - it's on nvme1n1p1

qherring · 2023-06-27 09:36:12

seth wrote:

We're still missing the grub.cfg (being the most relevant part here) - it's on nvme1n1p1

There is nothing in the /boot , so nothing to share

qherring · 2023-06-27 09:50:59

I just cant seem to figure out how to mount this in the terminal. I can mount it in the GUI but there is nothing in my home, boot, or .snapshots directories. So I am assuming it is only mounting the /root subvolume...

When I was doing a snapper rollback earlier today I was mounting this disk using: sudo mount /dev/mapper/cryptlvm -o subvolid=5 /mnt
however when I try than now it says: "mount: /dev/mapper/cryptlvm: can't find in /etc/fstab."

I am lost. I gave btrfs a try and im getting burned. I guess i should start over fresh.

Last edited by qherring (2023-06-27 09:58:08)

seth · 2023-06-27 09:57:15

nvme1n1p1 isn't btrfs but vfat, just mount it into /mnt/boot (or /boot from the chroot)

qherring · 2023-06-27 10:03:44

seth wrote:

nvme1n1p1 isn't btrfs but vfat, just mount it into /mnt/boot (or /boot from the chroot)

I really appreciate your patience.

here is the grub.cfg from nvme1n1p1

https://pastebin.com/Hzj7vg6Y

Last edited by qherring (2023-06-27 10:05:00)

seth · 2023-06-27 14:26:32

if [ x$feature_default_font_path = xy ] ; then
   font=unicode
else
insmod part_gpt
insmod cryptodisk
insmod luks2
insmod gcry_rijndael
insmod gcry_rijndael
insmod gcry_sha256
insmod btrfs
cryptomount -u b7b560e0-b889-4f66-a24e-90280eb81b2a
set root='cryptouuid/b7b560e0b8894f66a24e90280eb81b2a'
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root --hint='cryptouuid/b7b560e0b8894f66a24e90280eb81b2a'  df9abdc3-3c8a-4908-b91d-250cdddd73fe
else
  search --no-floppy --fs-uuid --set=root df9abdc3-3c8a-4908-b91d-250cdddd73fe
fi
    font="/@/usr/share/grub/unicode.pf2"
fi

This looks odd - not only is the indentation wrong but also the decryption is conditioned on the font.
Did you edit that file somehow?

nl6720 · 2023-06-27 15:09:43

With /boot being the ESP and thus not encrypted, you don't need to enable GRUB_ENABLE_CRYPTODISK.

https://pastebin.com/Hzj7vg6Y wrote:

	linux	/vmlinuz-linux root=UUID=df9abdc3-3c8a-4908-b91d-250cdddd73fe rw rootflags=subvol=@ cryptsetup refresh --allow-discards cryptlvm loglevel=3 quiet nvidia_drm.modeset=1

cryptsetup is a command you run, not a kernel parameter.

Post your /etc/default/grub.

qherring · 2023-06-27 15:53:46

seth wrote:

This looks odd - not only is the indentation wrong but also the decryption is conditioned on the font.
Did you edit that file somehow?

No, I only modified /etc/default/grub directly. Afterwards when I did sudo grub-mkconfig -o /boot/grub/grub.cfg it would have imported the changes I made.

Last edited by qherring (2023-06-27 15:54:26)

qherring · 2023-06-27 16:12:51

nl6720 wrote:

Post your /etc/default/grub.

https://pastebin.com/TBZ8xz9U

nl6720 · 2023-06-27 16:19:04

https://pastebin.com/TBZ8xz9U wrote:

GRUB_CMDLINE_LINUX_DEFAULT="loglevel=3 quiet nvidia_drm.modeset=1"
GRUB_CMDLINE_LINUX="cryptdevice=UUID=b7b560e0-b889-4f66-a24e-90280eb81b2a:cryptlvm rootfstype=btrfs"
GRUB_CMDLINE_LINUX="cryptsetup refresh —allow-discards cryptlvm"

The second GRUB_CMDLINE_LINUX overrides the first one. And as I said previously,

nl6720 wrote:

cryptsetup is a command you run, not a kernel parameter.

https://pastebin.com/TBZ8xz9U wrote:

# Uncomment to enable booting from LUKS encrypted devices
GRUB_ENABLE_CRYPTODISK=y

You don't need this since your kernel+initramfs is in an unencrypted partition (the ESP, which you mount at /boot). Comment out the GRUB_ENABLE_CRYPTODISK line.

Following https://wiki.archlinux.org/title/dm-cry … ives_(SSD) , you just needed to set GRUB_CMDLINE_LINUX to:

GRUB_CMDLINE_LINUX="cryptdevice=UUID=b7b560e0-b889-4f66-a24e-90280eb81b2a:cryptlvm:allow-discards"

Arch Linux

#1 2023-06-27 08:27:49

Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#2 2023-06-27 08:30:56

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#3 2023-06-27 08:36:36

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#4 2023-06-27 08:43:21

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#5 2023-06-27 08:44:54

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#6 2023-06-27 08:45:10

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#7 2023-06-27 08:46:30

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#8 2023-06-27 08:47:03

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#9 2023-06-27 08:56:50

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#10 2023-06-27 08:58:28

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#11 2023-06-27 09:00:47

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#12 2023-06-27 09:03:54

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#13 2023-06-27 09:10:04

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#14 2023-06-27 09:15:10

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#15 2023-06-27 09:17:56

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#16 2023-06-27 09:32:23

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#17 2023-06-27 09:36:12

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#18 2023-06-27 09:50:59

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#19 2023-06-27 09:57:15

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#20 2023-06-27 10:03:44

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#21 2023-06-27 14:26:32

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#22 2023-06-27 15:09:43

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#23 2023-06-27 15:53:46

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#24 2023-06-27 16:12:51

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

#25 2023-06-27 16:19:04

Re: Cannot boot, I broke grub by editing /etc/default/grub [SOLVED]

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